Origin of low-frequency dielectric dispersion in KH2PO4 and RbH2PO4 ferroelectric crystals

Abstract

We have measured the low-frequency dielectric dispersions in KH2PO4 and RbH2PO4 crystals. In the paraelectric phase both crystals were observed to be free of dielectric dispersion in the low-frequency region concerned. However, both of them exhibited the low-frequency dielectric dispersion in the ferroelectric phase. Our study of the temperature-dependent dielectric relaxation in the ferroelectric phase supports that the major part of the low-frequency dielectric dispersion observed should be originated from the domain wall relaxations rather than the heat diffusion central peak of recent reports.